The necessity to anneal material in such applications is mainly for ease of handling when the material is to be used in the manufacture of transformers windings, motor windings and the like. The annealing process also improves the electrical conductivity of the strip.
A known method for annealing non-ferrous strip material is to heat the material to anneal temperatures by electrical inductive effects. Thus the material is fed around a pair of spaced pulleys one of which has a double grooved rim made of an electrical conductive material. The incoming strip is fed to one of these grooves then around the other pulley, through an induction coil and to the other groove of the first-mentioned pulley, the strip material passing around the spaced pulleys in this mode on a continous basis to provide a continuously moving closed electrical loop.
As the stip material passes through the induction coil a current is induced in it and the flow of current raises the material to the required predetermined anneal temperature. During annealing the atoms or molecules of the material are "rearranged" rendering the material soft and pliable. Following annealing the material is quenched in order to metallurgically freeze the molecules in the soft state.
In another method the incoming and outgoing material makes contact in overlapping relationship in a single groove in one of the pulleys to complete the electrical loop. A rather complicated system of in-feed pulleys has to be employed in this procedure which leads to unsatisfactory performance especially when flat stip material is undergoing treatment.
These known methods have certain basic problems which, in addition to the above, include excessive electrical sparking or arcing between the strip material passing in the grooves and mechanical wear.